<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <!-- oninput  -->
  <form action="" oninput="x.value=parseInt(a.value)+parseInt(b.value)">
    <input list="browsers">

    <datalist id="browsers">
      <option value="Internet Explorer">
      <option value="Firefox">
      <option value="Chrome">
      <option value="Opera">
      <option value="Safari">
    </datalist>

    <!-- output -->
    0<input type="range" id="a" value="50">100
    +<input type="number" id="b" value="50">
    =<output name="x" for="a b"></output>
  </form>
</body>

</html>